Deep Brain Stimulation Leads to Long-term Improvement of Neuropathic Tremor due to Chronic Inflammatory Demyelinating Polyneuropathy: A Case Report

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a peripheral neuropathy caused by immune-mediated demyelination, causing tremors in 3.9%-58% of affected patients. This neuropathic tremor may persist after treatment and is known to be refractory to conventional medication. We present two cases of neuropathic tremor due to CIDP in which deep brain stimulation (DBS) over a long-term period led to marked improvement. Case 1: A 66-year-old woman presented with severe 2-3-Hz resting, postural, and kinetic tremors of both hands. The tremor was refractory to medication but improved well after bilateral VIM-DBS. However, 2 months after the procedure, the tremor worsened and was accompanied by sensory disturbance in the extremities. A diagnosis of CIDP was made, and treatment with corticosteroids and intravenous immunoglobulin achieved remission 6 months later. Although there was residual tremor after CIDP remission, it has been well controlled by DBS for the last 10 years. Case 2: A 56-year-old man presented with a 6-year history of CIDP after developing sensory dullness and tremors in the extremities. The CIDP had gone into remission 1 year previously and the sensory deficits had improved, but the tremors had gradually worsened: severe 8-12-Hz postural, kinetic, and resting tremors were present in both upper extremities. Right VIM-DBS was performed and the tremors on the left side showed marked improvement. Over the next 8 years, the tremors were well controlled and there were no relapses of CIDP. DBS may achieve long-term improvement of neuropathic tremor caused by CIDP if the CIDP is in remission.

Bilateral Low-Frequency Hearing Impairment After Microvascular Decompression Surgery

BACKGROUND

Hearing impairment is an important complication of microvascular decompression (MVD). In patients after MVD, we have occasionally noted slight to moderate hearing deterioration at low frequencies that is difficult to detect using pure tone average.

OBJECTIVE

To assess the incidence and features of low-frequency hearing impairment (LF-HI) after MVD and evaluate its associated factors.

METHODS

This single-center, retrospective observational study assessed the audiometric outcome of 270 patients who underwent MVD between January 2015 and December 2020. Preoperative and postoperative hearing levels were compared for each frequency. LF-HI was defined as a hearing deterioration of ≥15 dB at 125, 250, or 500 Hz. The incidence, symptoms, and associated factors of LF-HI were analyzed.

RESULTS

Statistical analysis of the patients overall demonstrated slight but significant decreases in the hearing level after MVD at lower frequencies on both the operative and contralateral sides. Eighty-one patients (30.0%) had LF-HI: 49 on the operative side, 24 on the contralateral side, and 8 on both sides, while pure tone average was worsened in 5 patients (1.8%). Subjective symptoms, including hearing deterioration, ear fullness, tinnitus, and dizziness, developed in 10.4% of the patients with LF-HI but improved subsequently within several weeks. "Older age" and "operative side" were associated with LF-HI.

CONCLUSION

Decreases in lower-frequency hearing levels in both the ipsilateral and contralateral (nonoperative) ears were observed after trigeminal neuralgia and hemifacial spasm surgery. LF-HI does not cause permanent symptoms but may be a noteworthy phenomenon, possibly involved in the contralateral hearing loss encountered occasionally after other types of posterior cranial fossa surgery.

Aspiration Surgery with Appropriate Antibiotic Treatment Yields Favorable Outcomes for Bacterial Brain Abscess

BACKGROUND

Even in the era of advanced medical treatment, brain abscess still has a high mortality rate. At our institution, brain abscess has been treated mainly using stereotactic or echo-guided aspiration followed by relatively long-term antibiotic treatment, achieving favorable outcomes. To evaluate the efficacy of our strategy involving less-invasive aspiration surgery and long-term selective antibiotic administration for brain abscess, a single-institution series of cases was investigated.

METHODS

We retrospectively reviewed and analyzed the medical records of 25 cases of brain abscess treated at Saitama Medical University Hospital between 2008 and 2021. The patients comprised 16 men and 9 women aged between 39 and 85 years (median 62 years). Neurosurgical intervention was performed for 23 (92.0%) of the patients and the remaining 2 received antibiotics alone.

RESULTS

Among the neurosurgery patients, 22 (95.7%) underwent echo-guided or stereotactic aspiration, and only 1 underwent craniotomy. Anaerobic bacteria were detected in 11 patients. In the surgical and conservative groups, the median duration of antibiotic treatment was 16 weeks and 23 weeks, respectively. Since 2014 when metronidazole first became available, it has replaced meropenem to cover anaerobic bacteria. The overall mortality rate was 4.0% and a favorable outcome (Glasgow Outcome Scale 4 or 5) was achieved in 76% of the patients. There was no surgical mortality or morbidity.

CONCLUSIONS

Most patients underwent aspiration surgery and achieved favorable outcomes. Along with antibiotic treatment for a sufficiently long period to cover anaerobes, this approach can be expected to yield good results.

[Technique of Microvascular Decompression for Hemifacial Spasm Based on Surgical Anatomy]

This article describes the anatomical approach and operative points of microvascular decompression for hemifacial spasm based on the author's personal experience with 1,000 cases. As vascular compression of the facial nerve is often quite caudal, it is necessary to ensure that the compressing arteries in this area are moved. Neither the vessels nor the prosthesis used to move them should not touch the root exit zone of the nerve(vascular transposition nerve isolation technique). It should also be emphasized that every effort should be made to avoid complications such as hearing impairment and postoperative subcutaneous spinal fluid accumulation.

SURG-21. STEREOTACTIC BIOPSY FOR DEEP SEATED BRAIN LESIONS USING THE LEKSELL STEREOTACTIC FRAME SYSTEM

PURPOSE

To evaluate the results of stereotactic biopsies.

PATIENTS AND METHODS

Fifty-two patients with intraaxial lesions suspected of brain tumor. The locations of lesions includes, 19 deep cerebral white matter, 9 basal ganglia, 10 thalamus, 4 midbrain and 6 pons. Patients age ranged from 9 to 86 years (median 65 years), 33 were men and 19 were women. Under local anesthesia the Leksell stereotactic frame was fixed and the MRI were taken. Neuroimages such as enhanced CT scan or PET study were also used as references. After MRI patients were transferred to OR and under general anesthesia, several samples were taken with 2.1mm diameter needle by aspiration. Most of the cases the biopsy was done through frontal lobe, but in some cases through temporal lobe or through cerebellum. The samples were taken deeper and nearer regions of the designed targets with same trajectory, also. If there were cysts, aspiration of the cyst was performed as much as possible. The trajectory should avoid sulci, cortical veins or ventricular system. After biopsy inside the needle were irrigated repeatedly with 0.1 - 0.2 ml saline using thin plastic tube until the fluid does not contain bloody fluids to ensure hemostasis.

RESULTS

In all patients appropriate samples for pathological diagnosis were obtained. The diagnoses were 28 gliomas (pilocytic 1, grade II 8, grade III 11, grade VI (GBM) 6, high grade 1, glial tumor 1), 17 lymphomas, 3 germinoma and 2 were non-tumorous pathology. There were no symptomatic bleeding nor neurological complications.

CONCLUSION

With detailed planning, stereotactic biopsy was safely performed even from basal ganglia or brainstem. Trajectories other than from frontal can be also considered for some lesions. Repeated irrigation with saline might effective to prevent symptomatic bleeding and this case series shows lower complication rates compared to the published literatures.

A Large Mass Mimicking Calcified Hematoma of the Skull Showing Involvement of Myeloma Cells and a Good Response to Irradiation

Patients with multiple myeloma often show skull bone involvement, although in most cases this is manifested as skull erosion and large masses develop only rarely. Here we report a patient who presented with a large cranial mass mimicking a subdural hematoma with calcification. The tumor shrunk with 37.5 Gy of focal irradiation in 15 fractions after biopsy. After irradiation the patient was treated with Bortezomib but died because of adverse events. The differential diagnosis of lenticular lesion of the skull and treatment strategy for large skull mass with myeloma cells are discussed.

Single-Site Non-Fermi-Liquid Behaviors in a Diluted 4f^{2} System Y_{1-x}Pr_{x}Ir_{2}Zn_{20}

Electrical resistivity ρ(T) and specific heat C(T) measurements have been made on the diluted 4f^{2} system Y(Pr)Ir_{2}Zn_{20}. Both data of ρ and magnetic specific heat C_{m} per Pr ion are well scaled as a function of T/T_{0}, where T_{0} is a characteristic temperature of non-Fermi-liquid (NFL) behaviors. Furthermore, the temperature dependences of ρ and C_{m}/T agree with the NFL behaviors predicted by the two-channel Kondo model for the strong coupling limit. Therefore, we infer that the observed NFL behaviors result from the single-site quadrupole Kondo effect due to the hybridization of the 4f^{2} states with multichannel conduction electrons.

Successful treatment of hemorrhagic congenital intracranial immature teratoma with neoadjuvant chemotherapy and surgery

Congenital intracranial immature teratomas carry a dismal prognosis, and the usefulness of chemotherapy for these tumors has not been elucidated. The authors report on the successful management of a case of congenital intracranial immature teratoma by using neoadjuvant chemotherapy and surgery after the failure of an initial attempt at resection. The patient was an infant who had begun vomiting frequently at the age of 12 days and had been admitted to a hospital at the age of 18 days with continued vomiting, increased head circumference, and disturbance of consciousness. A CT scan of the brain revealed a large mass in his posterior fossa and hydrocephalus. Surgery was performed on an emergent basis, but only minor tumor resection could be performed due to massive intraoperative hemorrhage. The histopathological diagnosis was immature teratoma. Postoperatively, the infant was in critical condition due to severe postoperative complications, and when he was transferred to the authors' institution 43 days after birth, his respiratory condition was still unstable because of lower cranial nerve palsy. Chemotherapy with carboplatin and etoposide resulted in moderate shrinkage of the tumor. Further chemotherapy led to improvement in the patient's general condition and weight gain, which allowed for a second attempt at resection. During this second surgery, which was performed when the child was 8 months of age, after 8 courses of chemotherapy, the tumor was completely resected with little bleeding. Histological findings from the second operation were consistent with mature teratoma. This case indicates that upfront chemotherapy may be effective for the initial management of such cases. Although the objective response to the treatment was modest, chemotherapy reduced the hemorrhagic nature of the tumor, facilitated improvement of the patient's general condition, and allowed for successful resection.

[Aquired stuttering in addition to a recurrence of developmental stuttering caused by brain tumor in the corpus callosum]

We reported a 66-year-old right-handed man, in whom developmental stuttering had almost been cured previously, who suffered a brain tumor. He developed not only left hemiparesis but also speech dysfluency such as acquired stuttering and aphasia. MRI showed a brain tumor in the body of the corpus callosum. The main feature of his stuttering was repetition of syllables. His stuttering was associated without secondary phenomena such as tongue clicking. His stuttering demonstrated no adaptation benefit and no consistency effect. These results suggest that the stuttering in this patient might have characteristics of both developmental and acquired stuttering, which in turn may suggest that after brain tumor, acquired stuttering occurs in addition to a recurrence of developmental stuttering.

Abstract 4144: Identification of molecules involved in PpIX accumulation in brain tumor induced by oral administration of 5-ALA

[Background and Purpose] 5-aminolevulinic acid (5-ALA) is one of leading compounds widely used in photodynamic diagnosis and therapy of solid tumors: 5-ALA is metabolically converted to protoporphyrin IX (PpIX), a fluorescent molecule in response to excitation with a laser beam of 405 nm wavelength, that accumulates specifically in tumor lesions. This is found to be very effective for intra-operative detection of malignant brain tumors such as glioblastoma multiforme (GBM). On the other hand, we occasionally encountered cancerous lesions that are apparently malignant under a white light, while showing no fluorescence of the PpIX during cyto-reductive operation of the GBM. In order to overcome this problem, we hereby searched for factors associated with either presence or absence of the PpIX fluorescence by means of comprehensive gene expression analysis.

[Materials and Methods] Thirty-one patients of brain tumor (21 GBM, 3 pilocytic astrocytoma and 7 oligodendroglial tumors), orally-administrated with 5-ALA followed by operation under a fluorescence-guide, were enrolled in this study. Tumor specimens with or without the 5-ALA induced-fluorescence were collected from these patients and snap-frozen in liquid nitrogen. Total RNAs were extracted from the frozen tissues and were subjected to a comprehensive gene expression analysis using Whole Human Genome 4×44K Oligo Microarray (Agilent). We then compared gene expression levels between specimens with or without the fluorescence among individuals and selected candidate genes of which gene expression levels significantly differ between these. For validation, quantitative gene expression analyses were conducted for the candidates with real-time RT-PCR using gene specific-primers and probes. Knockdown experiments using specific siRNAs were also performed in cell lines derived from GBM to test their biological significance.

[Results and Discussion] A total of 14 genes were initially selected as candidates that were associated with PpIX accumulation in GBM in the microarray analysis. Among these, CDH13 (cadherin 13) gene was expressed significantly higher in the fluorescence-positive GBMs than in negative ones. Knockdown of CDH13 gene expression in GBM cells treated with 5-ALA, attenuated the fluorescence intensity, indicating its possible role in PpIX accumulation. Further experiments are underway to elucidate molecular mechanisms of CDH13 in 5-ALA-induced PpIX fluorescence in brain tumor.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4144. doi:10.1158/1538-7445.AM2011-4144

Affinity-matured anti-glycoprotein NMB recombinant immunotoxins targeting malignant gliomas and melanomas

Glycoprotein NMB (GPNMB), a transmembrane glycoprotein highly expressed in high-grade gliomas (HGGs), is an attractive target in cancer immunotherapy. We isolated a GPNMB-specific scFv clone, G49, from a human synthetic phage-display library. To obtain mutant single-chain variable-fragment antibodies (scFvs) with improved affinity and immunotoxins with increased activity, we subjected G49 to in vitro affinity maturation by a complementarity-determining-region (CDR) random-mutagenesis technique. Using light-chain CDR3 mutagenesis, cell-based panning by phage display, subsequent heavy-chain CDR1 mutagenesis, and flow-cytometric selection by yeast-surface display, we generated the mutant scFv clone 902V, with an overall 11-fold increase in affinity for GPNMB. Clone 902V was further randomized throughout the whole scFv by error-prone PCR, and one mutant, F6V, was selected by yeast-surface display. F6V scFv, differing from 902V by one amino-acid change in the light-chain CDR2, exhibited an affinity for GPNMB of 0.30 nM. The F6V mutant scFv clone was fused with a truncated form of Pseudomonas exotoxin A to form the immunotoxin F6V-PE38. F6V-PE38 demonstrated significant protein-synthesis-inhibition activity on GPNMB-expressing glioma and malignant melanoma cells (IC(50) = 0.5 ng/ml [8 pM]), a 60-fold improvement over G49 activity, but no cytotoxicity on GPNMB-negative cells. Furthermore, F6V-PE38 exhibited significant antitumor activity against subcutaneous malignant glioma xenografts in two nude-mouse models and a melanoma neoplastic meningitis model in athymic rats. These GPNMB-specific scFv antibodies and immunotoxins hold promise as reagents in targeted therapy for HGGs and other GPNMB-expressing malignancies.

MRP3: a molecular target for human glioblastoma multiforme immunotherapy

Background

Glioblastoma multiforme (GBM) is refractory to conventional therapies. To overcome the problem of heterogeneity, more brain tumor markers are required for prognosis and targeted therapy. We have identified and validated a promising molecular therapeutic target that is expressed by GBM: human multidrug-resistance protein 3 (MRP3).

Methods

We investigated MRP3 by genetic and immunohistochemical (IHC) analysis of human gliomas to determine the incidence, distribution, and localization of MRP3 antigens in GBM and their potential correlation with survival. To determine MRP3 mRNA transcript and protein expression levels, we performed quantitative RT-PCR, raising MRP3-specific antibodies, and IHC analysis with biopsies of newly diagnosed GBM patients. We used univariate and multivariate analyses to assess the correlation of RNA expression and IHC of MRP3 with patient survival, with and without adjustment for age, extent of resection, and KPS.

Results

Real-time PCR results from 67 GBM biopsies indicated that 59/67 (88%) samples highly expressed MRP3 mRNA transcripts, in contrast with minimal expression in normal brain samples. Rabbit polyvalent and murine monoclonal antibodies generated against an extracellular span of MRP3 protein demonstrated reactivity with defined MRP3-expressing cell lines and GBM patient biopsies by Western blotting and FACS analyses, the latter establishing cell surface MRP3 protein expression. IHC evaluation of 46 GBM biopsy samples with anti-MRP3 IgG revealed MRP3 in a primarily membranous and cytoplasmic pattern in 42 (91%) of the 46 samples. Relative RNA expression was a strong predictor of survival for newly diagnosed GBM patients. Hazard of death for GBM patients with high levels of MRP3 RNA expression was 2.71 (95% CI: 1.54-4.80) times that of patients with low/moderate levels (p = 0.002).

Conclusions

Human GBMs overexpress MRP3 at both mRNA and protein levels, and elevated MRP3 mRNA levels in GBM biopsy samples correlated with a higher risk of death. These data suggest that the tumor-associated antigen MRP3 has potential use for prognosis and as a target for malignant glioma immunotherapy.

Glycoprotein nonmetastatic melanoma protein B, a potential molecular therapeutic target in patients with glioblastoma multiforme

PURPOSE

More brain tumor markers are required for prognosis and targeted therapy. We have identified and validated promising molecular therapeutic glioblastoma multiforme (GBM) targets: human transmembrane glycoprotein nonmetastatic melanoma protein B (GPNMB(wt)) and a splice variant form (GPNMB(sv), a 12-amino-acid in-frame insertion in the extracellular domain).

EXPERIMENTAL DESIGN

We have done genetic and immunohistochemical evaluation of human GBM to determine incidence, distribution, and pattern of localization of GPNMB antigens in brain tumors as well as survival analyses.

RESULTS

Quantitative real-time PCR on 50 newly diagnosed GBM patient tumor samples indicated that 35 of 50 GBMs (70%) were positive for GPNMB(wt+sv) transcripts and 15 of 50 GBMs (30%) were positive for GPNMB(sv) transcripts. Normal brain samples expressed little or no GPNMB mRNA. We have isolated and characterized an anti-GPNMB polyclonal rabbit antiserum (2640) and two IgG2b monoclonal antibodies (mAb; G11 and U2). The binding affinity constants of the mAbs ranged from 0.27 x 10(8) to 9.6 x 10(8) M(-1) measured by surface plasmon resonance with immobilized GPNMB, or 1.7 to 2.1 x 10(8) M(-1) by Scatchard analyses with cell-expressed GPNMB. Immunohistochemical analysis detected GPNMB in a membranous and cytoplasmic pattern in 52 of 79 GBMs (66%), with focal perivascular reactivity in approximately 27%. Quantitative flow cytometric analysis revealed GPNMB cell surface molecular density of 1.1 x 10(4) to 7.8 x 10(4) molecules per cell, levels sufficient for mAb targeting. Increased GPNMB mRNA levels correlated with elevated GPNMB protein expression in GBM biopsy samples. Univariate and multivariate analyses correlated expression of GPNMB with survival of 39 GBM patients using RNA expression and immunohistochemical data, establishing that patients with relatively high mRNA GPNMB transcript levels (wt+sv and wt), >3-fold over normal brain, as well as positive immunohistochemistry, have a significantly higher risk of death (hazard ratios, 3.0, 2.2, and 2.8, respectively).

CONCLUSIONS

Increased mRNA and protein levels in GBM patient biopsy samples correlated with higher survival risk; as a detectable surface membrane protein in glioma cells, the data indicate that GPNMB is a potentially useful tumor-associated antigen and prognostic predictor for therapeutic approaches with malignant gliomas or any malignant tumor that expresses GPNMB.

Okadaic acid stimulates the expression of vascular endothelial growth factor gene

Vascular endothelial growth factor (VEGF) is a specific mitogen for vascular endothelial cells and has been implicated in tumor angiogenesis. Okadaic acid, an inhibitor of protein phosphatases 1 and 2A, is a non-12-O-tetradecanoylphorbol-13-acetate (TPA)-type tumor promoter in two-stage carcinogenesis experiments in mouse skin. To elucidate the role of VEGF in the angiogenesis of these experimental tumors, the effect of okadaic acid on VEGF gene expression was examined. In NIH 3T3, Rat1, HeLa, and A431 cells, VEGF mRNA was upregulated by 5- to 10-fold after incubation with okadaic acid. Furthermore, the amount of VEGF protein in the culture medium was significantly increased after stimulation with okadaic acid. Interestingly, okadaic acid-induced upregulation of VEGF mRNA was not suppressed by protein kinase C (PKC) inhibitor or by tumor necrosis factor alpha blocking antibody, although TPA-induced VEGF upregulation was strongly suppressed by PKC inhibitor. Our results indicate that okadaic acid is a new and potent inducer of VEGF, suggesting the involvement of VEGF as an angiogenic factor during multistep carcinogenesis in vivo.

A cAMP response element and an Ets motif are involved in the transcriptional regulation of flt-1 tyrosine kinase (vascular endothelial growth factor receptor 1) gene

The flt-1 gene encodes a transmembrane tyrosine kinase, Flt-1, a receptor for vascular endothelial growth factor. The expression of flt-1 gene is restricted to endothelial cells in vivo. To understand the molecular mechanism underlying endothelial-specific expression of this gene, we studied the functional significance of transcriptional motifs in the 200-base pair region of the human flt-1 gene promoter, which has been identified to confer cell type specificity. By point mutation analysis using chloramphenicol acetyltransferase plasmids in 293E1 cells, which express significant levels of flt-1 mRNA, we found that an Ets motif, E4, at -54 to -51 and a cAMP response element (CRE) at -83 to -76 are involved in the transcriptional regulation of this gene. Disruption of either this CRE or E4 within the promoter sequence of 90 base pairs resulted in a decrease in chloramphenicol acetyltransferase activity of 90%, indicating that co-existence of both of CRE and Ets motif E4 is necessary for transcription of the flt-1 gene. Co-transfection of an expression vector containing c-ets-1, c-ets-2, or c-erg cDNA with this 90-base pair sequence yielded a 5-8-fold elevation of chloramphenicol acetyltransferase activity, further supporting the idea that Ets family protein(s) participates in the regulation of the flt-1 gene. Gel shift assays using nuclear extracts of 293E1 and endothelial cells demonstrated the existence of protein factor(s) that specifically binds to CRE and Ets motif E4, respectively. Taken together, our results strongly suggest cooperation of a CRE and an Ets motif for the function of the flt-1 gene promoter.

Characterization of the promoter region for flt-1 tyrosine kinase gene, a receptor for vascular endothelial growth factor

The flt-1 gene encodes a Vascular Endothelial Growth Factor receptor, (Flt-1), whose expression is restricted to vascular endothelial cells. To characterize the cell type specificity of flt-1 gene expression, we isolated the upstream genomic DNA of the human flt-1 gene and identified a single transcription initiation site 29 bp downstream of a TATA box. DNA sequencing revealed that one TATA box, four GC boxes, nine ETS motifs and one CRE motif were present in the upstream 489 bp region of exon 1. Functional analyses using CAT plasmids in 293E1 cells, which express significant levels of the flt-1 gene, showed that the -229 to +8 region is essential for the cell type-specific expression of this gene. Deletion mutant analysis also pointed to the possible existence of negative and positive regulatory elements in the region -911 to -435, and +8 to +276, respectively. These results suggest that multiple regulatory factors are involved in the transcriptional regulation of the flt-1 gene expression in a cell type-specific, or a more ubiquitous manner.

[Results of microvascular decompression in 16 cases of glossopharyngeal neuralgia]

Seven males and nine females with glossopharyngeal neuralgia were treated by microvascular decompression (MVD) over a 4-year period. Their ages ranged from 40 to 72 years (average, 54.7 years). The duration of pain ranged from 2 months to 13 years, and all except one patient had brief attacks of lancinating pain in the throat and/or ear. One patient reported dull, paroxysmal throat pain. At surgery, vascular compression of the 9th and 10th nerves at the root entry-exit zone was observed in all cases. The offending vessels were the posterior inferior cerebellar artery (PICA) in 11 cases, the PICA and the anterior inferior cerebellar artery (AICA) in two, the PICA and vertebral artery (VA), and AICA and VA in one case each. The patient with atypical pain had compression by a large vein. In 15 cases of arterial compression, the pain completely disappeared after MVD, and there was no recurrence during the follow-up period, which ranged from 1 month to 4 years. One patient with venous compression had significant pain relief, although mild throat pain persists. In one case, postoperative complications included transient 6th, 7th, and 10th nerve palsies and sensory disturbance, which were assumed to be due to disturbance of the circulation in the perforating branches from the compressing artery. The experience with these 16 patients indicates that vascular compression is the etiology of glossopharyngeal neuralgia and that MVD provides excellent results.